The invention relates generally to steerable catheters, and more particularly to a steerable catheter having a handle with a steering controller that has a self-locking mechanism that allows the catheter profile to be changed and locked in place through the single-handed manipulation of the steering controller.
In many medical procedures, it is necessary to place a catheter at a particular location within the patient""s body. Precise placement of the catheter is more easily accomplished when a steerable catheter is used. Such catheters are typically flexible at the distal end, and the profile at the distal end is adjustable.
Changing the profile of the distal-end region of a steerable catheter typically involves the use of a steering tendon that is housed within the catheter shaft. The steering tendon is usually a wire that has its distal end attached to the distal-end region of the catheter shaft. The proximal end of the catheter shaft attaches to a handle. The proximal end of the steering tendon exits through the proximal end of the catheter shaft and attaches to a steering controller within the handle.
The profile of the distal-end region of the catheter shaft can be adjusted from its non-steered configuration by manipulating the steering controller from a neutral position so that the steering tendon is axially displaced in the proximal direction. Axially displacing the steering tendon in the proximal direction places the steering tendon in tension. Placing the steering tendon in tension, in turn, causes the catheter shaft to compress preferentially on the side where the steering tendon is attached. This causes a deflection of the distal-end region. If the steering controller is released, the distal-end region of the catheter shaft typically springs back to its natural state due to the structure of the catheter shaft, thus moving the steering tendon and the steering controller back to their neutral positions.
It is often necessary to maintain the force exerted on the steering tendon during the course of a medical procedure so as to retain the deflected profile of the distal-end region of the catheter. In some of the existing steerable catheters, maintaining the force exerted on the steering tendon requires the operator to manually hold the steering controller in place. However, it is often difficult for the operator to maintain a constant amount of force on the steering tendon for an extended period of time or while further manipulating the handle.
In other existing steerable catheters, an additional knob attached to the steering controller is used to lock the displacement of the steering tendon at its present position. This knob is used to tighten the steering controller against a friction plate within the handle housing until the resulting friction is sufficient to prevent the steering controller from moving from its present position. Typically, the operator must turn this knob with one hand while the other hand is used to maintain the preferred position of the steering controller relative to the handle housing. Thus, locking the steering controller in other steerable catheters is a two-handed operation.
Hence, those skilled in the art have identified a need for an improved catheter handle, and one with a steering controller that can be manipulated to a new position and locked in place through a single-handed operation. The present invention fulfills these needs and others.
Briefly, and in general terms, the present invention is directed to a catheter handle with a steering controller that includes a self-locking mechanism to be used in steering a single or multiple-profile catheter. The steering controller can be manipulated to establish a new profile of the catheter and locked in place with the self-locking mechanism through a single-handed operation.
In a first aspect, the invention relates to a handle for steering a catheter shaft that has a proximal region and a distal-end region and at least one steering tendon. The steering tendon has a distal end attached to the shaft distal-end region and a proximal end that exits the proximal end of the shaft. The handle includes a shell housing that is attached to the proximal end of the catheter shaft. The handle also includes a steering controller that is carried by the shell housing and has the proximal end of the at least one steering tendon connected thereto. The steering controller is adapted for movement to apply tension to the at least one steering tendon. Further included in the handle are a means for retaining the steering controller in a locked position to prevent the steering controller from moving, and means for moving the steering controller from the locked position to a free position wherein the steering controller is manipulable to adjust tension to the least one steering tendon.
In a detailed aspect of the invention, the steering controller includes a rotatable steering knob that includes a shaft portion located internal the shell housing and a controller portion located external the shell housing. The steering controller also includes a rotatable steering disk located internal the shell housing and attached to the shaft portion of the knob. In another detailed aspect, the retaining means includes first mating means that are carried by the shell housing, second mating means that are carried by the steering controller, and means for biasing the second mating means against the first mating means such that the first and second mating means engage. In a more detailed aspect, the first mating means and the second mating means each comprise a plurality of alternating protrusions and recesses. In a further detailed aspect, the plurality of alternating protrusions and recesses form teeth. In another detailed facet, the handle further includes means for adjusting the force with which the biasing means biases the second mating means against the first mating means. In a more detailed facet, the adjusting means includes a screw. In a further detailed facet, the biasing means includes any one of a compression spring, tension spring, leaf spring and Belleville spring washers. In another detailed facet, the means for moving the steering controller includes means for receiving force sufficient to disengage the second mating means from the first mating means. In a further detailed facet, the steering controller includes a rotatable steering knob that has a shaft portion located internal the shell housing and a controller portion located external the shell housing, and the force-receiving means include the controller portion.
In a second aspect, the invention relates to a handle for steering a catheter shaft that has a proximal region and a distal-end region and at least one steering tendon. Each steering tendon has a distal end attached to the shaft distal-end region and a proximal end that exits the proximal end of the shaft. The handle includes a shell housing that is attached to the proximal end of the catheter shaft and has a plurality of alternating protrusions and recesses positioned within the shell housing. The handle also includes a steering controller that is carried by the shell housing and has a plurality of alternating protrusions and recesses positioned within the shell housing. The proximal end of the at least one steering tendon is connected to the steering controller. The steering controller is adapted to translate between a locked position and a free position. In the locked position, at least one of the steering controller protrusions and recesses is engaged with at least one of the shell housing protrusions or recesses. In the free position, the steering controller protrusions and recesses are disengaged from the shell housing protrusions and recesses and the steering controller is manipulable to adjust tension to the least one steering tendon.
In a detailed aspect, the plurality of protrusions and recesses form teeth. In a more detailed aspect, the steering controller includes a rotatable steering knob that includes a shaft portion located internal the shell housing and a controller portion located external the shell housing. The steering controller further includes a rotatable steering disk that carries the steering controller protrusions and recesses. The steering disk is located internal the shell housing and is attached to the shaft portion of the knob. The steering controller also includes a spring for biasing the steering disk toward the shell housing protrusions and recesses such that the steering controller protrusions and recesses engage at least one of the shell housing protrusions and recesses. In an even more detailed aspect, the steering controller protrusions and recesses are located along the perimeter of the steering disk. In another detailed facet, the force with which the spring biases the steering disk in the locked position is adjustable. In another detailed aspect, the steering controller further includes a spacer that is located internal the shell housing and is attached to the shaft portion of the knob. In a more detailed aspect, the spring biases the steering disk via the spacer. In an even more detailed aspect, the spring includes any one of a compression spring, tension spring, leaf spring and Belleville spring washers, and the biasing force is adjustable via a screw. In a further detailed aspect the steering disk is disengaged from the shell housing via the application of force upon the steering knob that opposes the biasing force.
In a third aspect, the invention relates to a catheter that includes a catheter shaft that has a proximal region and a distal-end region and at least one steering tendon. The steering tendon has a distal end that is attached to the shaft distal-end region and a proximal end that exits the proximal end of the shaft. The catheter also includes a shell housing having the proximal end of the shaft attached thereto. The shell housing includes a plurality of alternating protrusions and recesses positioned within the shell housing. The catheter also includes a steering controller that is carried by the shell housing. The steering controller has a plurality of alternating protrusions and recesses that are positioned within the shell housing. The proximal end of the at least one steering tendon is connected to the steering controller. The steering controller is adapted to translate between a locked position and a free position. In the locked position, at least one of the steering controller protrusions or recesses is engaged with at least one of the housing protrusions or recesses. In the free position, none of the steering controller protrusions or recesses is engaged with any of the housing protrusions or recesses and the steering controller is manipulable to apply or release tension to the steering tendon.
In a detailed aspect of the invention, there is at least one electrode positioned at the distal-end region of the shaft. In a further aspect of the invention, the steering controller includes a rotatable steering knob that includes a shaft portion located internal the shell housing and a controller portion located external the shell housing. The steering controller farther includes a rotatable steering disk located internal the shell housing that is attached to the shaft portion of the knob. The steering disk carries the steering controller protrusions and recesses. The steering controller also includes a spacer located internal the shell housing that is also attached to the shaft portion of the knob, and a compression spring that biases the steering disk, via the spacer, toward the shell housing protrusion and recesses such that the steering controller protrusion and recesses engage at least one of the shell housing protrusion and recesses. In a more detailed aspect, the force with which the compression spring biases the steering disk in the locked position via the spacer is adjustable.
In a fourth aspect, the invention relates to a method of steering a catheter shaft that has at least one steering tendon by using a handle that includes a shell housing with a plurality of alternating protrusions and recesses and a rotatable steering controller that also has a plurality of alternating protrusions and recesses. The housing protrusions and recesses are normally engaged with the controller protrusions and recesses by a biasing force. The method includes the step of disengaging the controller protrusions and recesses from the housing protrusions and recesses. The method also includes the step of rotating the controller to pull on the at least one steering tendon and thereby deflect the profile of the shaft. Also included is the step of reengaging the controller protrusions and recesses with the housing protrusions and recesses.
In a detailed aspect of the invention, the step of disengaging the controller protrusions and recesses from the housing protrusions and recesses includes opposing the biasing force with a force greater than the biasing force. In another aspect, the step of reengaging the controller protrusions and recesses with the housing protrusions and recesses comprises opposing the biasing force with a force less than the biasing force.
These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings, which illustrate by way of example the features of the invention.